title: Comparative performance of mesophilic and thermophilic anaerobic digestion for high-solid sewage sludge.
abstract: In local cities, many small sewage and waste treatment facilities are operated independently. To encourage processing by anaerobic digestion at a centralized sewage treatment plant (STP), high-solid sewage sludge is helpful because it reduces the energy and cost required for transporting the sludge from other STPs. Mesophilic and thermophilic anaerobic digestion of sewage sludge at total solids concentrations (TS) of 7.5% and 10% were evaluated using laboratory-scale continuous reactors. Under the mesophilic condition, sewage sludge of 10% TS was successfully treated. Under the thermophilic condition, sewage sludge of 7.5% TS was not successfully treated when the total ammonia concentration was over 2000 mg N/L. Batch experiments showed that it takes a few weeks for the methane fermentation activity to recover after being inhibited. The effectiveness of adding easily biodegradable organic matter was confirmed. These results show that high-solid sewage sludge is suitable for small facilities by controlling the operating conditions.
authors.affiliation: Recycling Research Team, Materials and Resources Research Group, Public Works Research Institute, 1-6, Minamihara, Tsukuba, Ibaraki 305-8516, Japan. Electronic address: hidaka@pwri.go.jp.
authors.forename: Taira
authors.initials: T
authors.lastname: Hidaka
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Taketo
authors.initials: T
authors.lastname: Togari
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Uchida
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Suzuki
mesh_terms: D000641:Ammonia / Q000032:analysis; D000693:Anaerobiosis; D061249:Batch Cell Culture Techniques; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D006863:Hydrogen-Ion Concentration; D008697:Methane / Q000378:metabolism; D009584:Nitrogen / Q000032:analysis; D012722:Sewage / Q000382:microbiology*; D013696:Temperature; D014783:Viscosity; D014835:Volatilization; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D012722:Sewage; D000641:Ammonia; D009584:Nitrogen; D008697:Methane
keywords: Ammonia inhibition; Anaerobic digestion; High-solid sewage sludge; Small facilities; Thermophilic